Ventilatory Patterns PDF

VENTILATION Tamethia Perkins MS, RRT-NPS, RRT-ACCS RT 3005/6005 Ventilatory Patterns  Normal Ventilatory Pattern ◼ Consists of: ◼ Tidal Volume (VT) ◼ Ventilator Rate (RR) ◼ Inspiratory to Expiratory Ratio (I:E) ◼ VT is the V of air that moves in and out o...

VENTILATION Tamethia Perkins MS, RRT-NPS, RRT-ACCS RT 3005/6005 Ventilatory Patterns  Normal Ventilatory Pattern ◼ Consists of: ◼ Tidal Volume (VT) ◼ Ventilator Rate (RR) ◼ Inspiratory to Expiratory Ratio (I:E) ◼ VT is the V of air that moves in and out of the lungs in one quiet breath. ◼ VT= 7-9 mL/kg. ◼ RR= ~ 15 bpm. (12-20) ◼ I:E = 1:2. (1:ins)+ (1:exp, 1:pause). Normal Ventilatory Pattern Alveolar Ventilation vs. Dead Space Ventilation ◼ Alveolar ventilation: inspired air that reaches the alveoli for gas exchange. ◼ Deadspace ventilation: inspired gas that does not reach the alveoli. ◼ Dead space: ◼ Anatomic ◼ Alveolar ◼ Physiologic Alveolar Ventilation vs. Dead Space Ventilation  Anatomic Dead Space ◼ Volume of gas in the conducting airways. ◼ Normal: 1ml/lb (2.2 mL/kg). ◼ ~150 mL. ◼ VA= (VT-VD) x breaths/min. ◼ Example: ◼ VT=450 mL ◼ VD=150 mL ◼ RR= 12 bpm ◼ VA= ? ◼ VA= 3.6L Anatomic Dead Space  Anatomic Dead Space ◼ Breathing pattern can alter total VA. ◼ Depth ◼ Rate  Alveolar Dead Space ◼ Alveolus is ventilated but not perfused with pulmonary blood. Physiologic Dead Space ◼ Sum of anatomic dead space and alveolar dead space.  Intrapleural P and Regional Ventilation ◼ Individual in upright position. ◼ Ppl at the apices = -7 to –10 cm H2O. Alveoli in the upper regions are expanded (almost total filling capacity) more than alveoli at the bases. ◼ Ppl at the bases = -2 to –3 cm H2O. More blood flow at the bases = heavier = more P for support = gravity-dependent. ◼ Alveoli at the apices have lower compliance than the alveoli at the bases. ◼ Ventilation is much greater and more effective in the lower lung regions.  Intrapleural P and Regional Ventilation Effects of Raw and CL on Ventilatory Patterns ◼ Normal: RR 15 bpm / VT 500mL. ◼  CL : ◼  RR ◼  VT ◼  Raw : ◼  RR ◼  VT ◼ The change in ventilatory pattern is thought to be based on minimum work requirements rather than ventilatory efficiency. Effects of Raw and CL on Ventilatory Patterns  Specific Ventilatory Patterns APNEA ◼ Complete absence of spontaneous ventilation. EUPNEA ◼ Normal, spontaneous breathing. BIOT’S BREATHING ◼ Rapid deep inspirations followed by 10-30 seconds of apnea. Meningitis. Specific Ventilatory Patterns  Specific Ventilatory Patterns HYPERPNEA ◼ Increased depth of breathing with or without increased RR. HYPERVENTILATION ◼ Increased VA ( RR or  VT). HYPOVENTILATION ◼ Decreased VA ( RR or  VT). Specific Ventilatory Patterns Hyperventilation Hypoventilation  Specific Ventilatory Patterns TACHYPNEA ◼ Increased RR. CHEYNE-STOKES BREATHING ◼ Gradual increase in volume and rate followed by a gradual decrease in volume and rate until a period of apnea of 10-30 seconds. ◼ Cerebral disorders. Cheyne-Stokes  Specific Ventilatory Patterns KUSSMAUL BREATHING ◼ Increased depth and rate of breathing. ◼ Diabetic ketoacidosis. ORTHOPNEA ◼ The individual is able to breath most comfortably in upright position. DYSPNEA ◼ Difficulty in breathing. Kussmaul